Cable for communication circuits



Feb. 27, 1934. E FlsCHER 1,948,616

CABLE FOR COMMUNICATION CIRCUITS Filed July 2l, 1930 Y lllllllllllr ,1111111111 5.1.@

Patented Fel). 27, 1934 v V1,948,616 CABLE Foa COMMUNICATION CIRCUITS Ernst Fischer, Berlin-Lichterfelde-West, Germany, assignor to Siemens-Schuckertwerke Aktiengesellschaft, Berlin-Siemensstadt, Germany, a corporation of Germany Application July 21, 1930, Serial No. 469,418, and

in Germany July 27, 1929 3 Claims. (Cl. T13- 81) My invention relates to cables for communicathe interior ofthe cable core and the lead sheathtion circuits, hereafter called communication. ing. cables, and specifically to cables of that kind in My invention is illustrated in the accompanying which shields situated in the interior of the cable drawing in which 5 core are continuously grounded. Fig. 1represents a view, partly in longitudinal e0 For the purpose of grounding the metallicsection of one modification, sheaths or envelopes arranged inside the core oi Fig. 2 represents a transverse section of the communication cables to'shield individual speak` cable on line 2 2, Fig. 1,: ing circuits or groups of speaking circuits, hither- Fig. 3 represents a second modification, partly l' to, nettle-cloth tapes were generally used which in full view, partly in section,` and 65 are interwoven with thin metal wires. Such Fig. 4 represents a 'transverse section vof the tapes, however, have the disadvantage that often cable on line 44, Fig. 3. when they are being applied to the cable core or Fig. 1 shows a cable core 2, metallically shielded when the cable is bent, some of the wires break at 5, and to which two metallized paper tapes 3 l5 owing tothe pull exerted upon the thin wires, and and 4 are, according to the invention, applied in 70 that for this reason a continuous grounding is not such a manner that the metallized side of vtape 3, possible. There is the further danger of the indicated by a thickened line in the sectioned broken Wires puncturing the insulation of the portion, lies against the metallic shield 5, whilst wires and causing cable faults. the metallized side of tape 4, also indicated by a According to the invention, these disadvantages thickened line in the sectioned DOItOn, 'lies partly 75 are avoided by employing the well-known metalagainst the metallic Side 0f th tape 3 and partly lized tapes to ground the shields but in such a against the outer lead sheathing 6. In the full manner as to ensure a continuous reliable groundview portions of Fig. 1 the metallized sides of the ing along the whole length of the cable. Prefertapes are stippled. ably two tapes are used for this purpose, one of The cable core 2 consists of a plurality of 80 which is turned with its metallic side towards the groups of conductors. each group 0f which conspeaking circuits, i. e., toward the metallic enve- Sists 0f a OOIlVentiOnal plurality 0f Conductors, lopes or shields, whereas the metallic side of the such as ,quads 15, 16 and 17. In Fig. 1 nOt al1 other tape is turned outwardly toward the lead quads are Visible- Each quad 0f insulated 00nsheathing. The two tapesare wound spirally ductors may be Wrapped as shown at 14, in any 85 round the bundles o'f speaking circuits, or the conventional manner, which-forms no part ofthe cable core in such a manner that theirmetallic Present invention The quads are SiurOunded by sides are in Contact with each other over a certain a metallic Shield 5 Which thus iS in C0ntaCt`With tape breadth. When using only one tape it is also the Wrappings 14 0f the quads. Thus it Will be possible to obtain a sure, continuous grounding by Seen from the OIegOing, that incase the Wrap- 90 folding the tape before it is wound round the core pings 14v are Provided With a Shielding, Which is of a cable in such a manner that a part of the metthe conventional construction in such cables, the

allized side lies towards the core, while the other individual quad Shieldings become conductiveiy part of the metallized side is turned outwardly Connected through Shielding 5 by Way 0f the 40 toward the lead sheathing Another possibility metallized tape insulations 3, 4 to the outer cable 95 is to apply, for example by means of a double sheathing 6- spinning machine, alternately an insulating :ind In 3 and 4 a modlcatlqn 0f Silch a' Wrap' a conducting tape of tin-foil or the like in such a ping 1s Illustrated m connection Wlt'h' a' cable' manner that half of the one tape overlaps half whose core 2 may likewise consist of a plurality f the other; or a .conductmg layer may be f 01 de d of conventionally constructed groups of conduc- 100 tors 15, 16, 17. All the groups are surrounded by round one edge of an insulating tape and the tape r. wo d in .such a manner that the conducting a common shield 12 which connects any indu idual shieldin f h layer makes a good contact both with the -lead gs o t e Wrappmgs 14 of the groups but in this case the outer nietallized tape winding sheathing and with the metallic sheaths round the consists of a single tape 13 which is applied to 1Q i lspeaking circuits or group of speaking circuits` the metallic core shield 12. In order to estab- In many cases it 1s suiiicient to place separate 'lish a metallic connection between the'core shield metallic strips between the insulating tapes in 12 and the outer sheathing 6,-this tape 13 is foldsuch a manner that said strips forma good electried partly back on itself in longitudinal direction,

4cal connection between the metallic envelopes in as shown in Fig. 3, in such a manner that a part f 110 of its metallized side, also indicated by a. thickened line in the sectioned portion of Fig. 3, and stippled in the full View portion, lies against the core shield 12, and the remaining part of the metallized side faces outwardly, so that it comes to lie against the cable lead sheathing 6 when the latter is applied to the cable.

I claim as my invention:-

1. In a cable of the character described, in combination with a core containing a plurality of groups of insulated conductors, a metallic shielding for said groups and a common outer metallic cable sheathing for said groups, of an overlapping insulating tape winding arranged in superposed layers and enveloping said shielded groups, the tape, of which said winding is composed, being metallized on one face only, the metallized face of the innermost layer being in electrical contact with the metallic shielding of said individual conductor groups, the metallized face of the outermost layer contacting with said outer metallic cable sheathing, and the metallized face of each layer contacting with the metallized face of its adjacent layer, to electrically connect the group shielding with said outer cable sheathing.

2. In a cable of the character described, in combination with a core containing a plurality of groups of insulated conductors, a metallic shielding for said conductor groups and an outer common metallic cable sheathing for said groups, of an overlapping winding of two non-conducting tapes enveloping all of said groups, said tapes being metallized on one side only and facing one another with their metallized sides, and being wound to only partly overlap one another, so that one part of the metallized side of one winding electrically contacts with the group shielding and one part of the metallized side of the other winding contacts with said cable sheathing, whereby a continuous metallic contact .is established between said group shielding and said cable sheathing.

3. In a cable of the character described, in combination with a corel containing a plurality of groups of insulated conductors, a metallic shielding for said conductor groups and an outer common metallic cable sheathing for said groups, of an overlapping winding of one non-conducting tape, metallized on one side only and being folded lengthwise partly back on itself with the metallized side outside, and being wound to envelop said shielded groups with the non-folded portion of kone turn overlapping the folded portion of the preceding turn, whereby the metallized side of said tape establishes a continuous metallic Contact between said group shielding and said cable sheathing.

ERNST FISCHER. 

